Common practice is to form bumper beams for vehicles, particularly cars, of a high strength steel.
The bumper beam of this invention is preferably formed of a lighter weight material such as aluminum, plastic or magnesium. The bumper beam has a tubular cross-section so as to be still lighter in weight, and lower in cost.
The lightweight materials used in the fabrication of the beam are relatively weak structurally, as compared with high strength steel. Therefore, a reinforcement is provided internally of the hollow beam. The provision of reinforcement permits the walls of the beam to be relatively thin. Thinner walls are advantageous in further reducing the weight of the bumper beam.
The bumper beam must be able to withstand low speed impacts without collapsing. The reinforcement, preferably in the form of an S-shaped web, accomplishes this. However, the bumper beam must be capable of collapsing evenly upon a high speed impact. This results in absorbing energy of an accident and improves vehicle safety. The S-shape of the web results in the desired even collapsing of the bumper beam.
An object of this invention is to provide a bumper beam having the foregoing features.
Other objects are to provide a bumper beam which is rugged and durable in use, and capable of being easily and inexpensively manufactured.
Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered in conjunction with the accompanying drawings.